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From: liz@poppyrecords.invalid.invalid (Liz Tuddenham)
Newsgroups: sci.electronics.repair
Subject: Is it a capacitor, is it a resistor?
Date: Thu, 14 Mar 2024 20:56:32 +0000
Organization: Poppy Records
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I was asked to repair a Pioneer QX-949 quadraphonic tuner/amplifier.  It
is a complex beast and one channel had gone down to almost nothing.
Luckily the service sheet was available and I traced the fault to the
board which houses the tone controls and filters.

The gain is in two stages with the tone controls around the second
stage.  On one of the channels, the voltages on the single transistor
for that stage were all wrong.  After lifting the transistor off the
board, it became apparent that the base bias was far too high and the
finger of suspicion pointed to the inter-stage coupling capacitor
feeding in leakage current from the preceding stage.

I tested the capacitor, which was marked "4.7".  It read exactly 4.7k in
both directions on an ohm-meter !!!

-- 
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk